A federal task force says about 206 million gallons of oil gushed out of the busted rig, but more than 33 million gallons were contained. That means 172 million gallons made it into the Gulf between April and mid-July, when a temporary cap stopped the flow.
Based on that estimate, BP could be fined up to $5.4 billion under the Clean Water Act. The fine could soar to $21 billion if the oil company is found to have committed gross negligence or willful misconduct.
If the government credits BP for the oil it has recovered, the fine would range between $4.5 billion and $17.6 billion.
Any fines will be on top of the $20 billion escrow fund the company has set up to pay damage claims.